There is a bug that makes it possible to have a name on dualthegame.com twice. Therefore the board profile ID is added as suffix to the discord nickname. It is recommended to leave this suffix @1234 enabled as long as NovaQuark has not removed this bug. This is the only way for third parties to distinguish two users with the same name.
I will not tell you how this bug works. It doesn't work without further ado. But I will prove to you with my profile that there is such a bug.
My original account:
https://community.dualthegame.com/accounts/profile/codepeon/
My test account:
https://community.dualthegame.com/accounts/profile/CodePeon/
Even if the name of my original account is written in lower case in the URL, the nickname is still "CodePeon". You can check this by copying "CodePeon" from the page and pasting it somewhere else. Then you will see that the letters C and P are upper case. So both names are written identically. Of course I already reported this bug to NovaQuark.
So don't give fakers a chance and keep the suffix @1234 enabled!